Screw-plate



(No Model,) 3 Sheets-Sheet 0. POIROT. SCREW PLATE.

1%. 567,408. Patented-Spt. 8, 1896.

WITNESSES:

I ATTORNEYS 9 t e e h s t e e h. S 3 TE 0 L B? 0 PM w 0 q d 0 M o W No. 567,408. Patented Sept. 8, 1896.

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) B) Y W Q /WM- v ATTORNEYS tensions b, on which are shoulders b.

U ITED STAT S PATENT OFFICE.

OELESTIN POIROT, OF ERIE, PENNSYLVANIA.

SCREW-PLATE.

SPECIFICATION forming part of Letters Patent No. 567,408, dated September 8, 1896. Application filed January '7, 1896. Serial No. 574,604. (No model.)

the county of Erie and State of Pennsylvania,

have invented certain new and useful Improvements in Screw-Plates and I do hereby declare the following to be a full, clear, and

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to screw-plates and it consists in certain improvements in the construction thereof, as will be hereinafter fully described, and pointed out in the claim.

The invention is illustrated in the accompanying drawings, as follows:

Figure 1 shows a front elevation of the screw-plate, the face-plate being removed to better show construction. Fig. 2 shows a section on the line 2 2 in Figs. 1 and 3. Fig. 3 shows a section on the line 3 3 in Fig. 2.

A' marks the stock, in the front face of which are grooves a, which form guides for the dies B. Immediately back of the guidegrooves the diameter of the stock is enlarged, forming a shoulder A Back of the shoulder A the diameter of the stock is again reduced, and its periphery is providedwith ratchetteeth a andnotches a To the rear of the stock proper is attached what I term the guide-stock A, in the face of which are grooves a, which form guides for the guidepins B. This guide-stock has a shoulder A of the same diameter as the shoulder A the outer portion containing the groove a being of substantially the same diameter as the outer part of the stock.

The outer ends of the dies have small ex- There is a cam-ring 0, provided with cam-faces 0 one for each die. On the under sides of the cams are shoulders c, which engage the shoul ders b to draw the dies away from the center or away from the work, (the pipe F.)

The cam-ring is provided with a handle 0, with which it can be turned to drive the dies to or from the work. It will be noticed that the cam-surface 0 that drives the dies to the work, acts upon nearly the entire width of the die, making a large wearing-surface, and as the force of the movement is exerted directly on the end of the die the die has no tendency to tilt and so cause friction or binding in the die guide or grooves.

The dies and cam-ring are of such width and thickness, respectivelyQas to come just flush with the surface 'of the stock, and a plate D is attached to the stock, holding them securely in place.

At the rear of the screw-plate the guide A, the grooves a, the guide-pins B, the extensions o the shoulders 5 the cam-ring 0 having cam-faces C the cam-shoulder c, the handle 0 and face-plate D are shaped and arranged as are the stock A, the grooves a, the dies B, the extensions 6, the shoulders I), the cam-ring 0, having cam-faces C the camshoulder c, the handle 0, and face-plate D, respectively, the guide-pins of course being blunt instead of having a cutting edge, as the dies. The office of the guide-pins is to keep the screw-plate in line with the work, so that l the dies will start properly.

Between the shoulders A and A and journaled on the stock over the ratchet-teeth a is the ratchet-ring E. Two handle-sockets E extend from opposite sides of this ring, into which are placed the handles (not shown) for operating the plate. Two perforated lugs e on the ring E carry ratchet-pawls e, which are provided with stop-surfaces e and a beveled or escapement surface e The pawls are round and are extended by a pin e out of the lug e, and are provided with a milled thumb-cap e. A spring 6 is coiled around the pin 8 the tension of which presses the pawl into engagement with the ratchetteeth a By reference to Fig. 3 it will be seen that i if the ratchet-ring is turned to the right the stock and dies will be carried with it,while in the return movement the beveled surfaces 6 carry the pawls over the teeth, so that the stock remains stationary. ]3y takinghold of the thumb-cap and pulling one of the pawls out and turning it around andtheniallowing it to return to position the ratchetring will be locked with the stock. By reversing both pawls we have a left-hand-ratchet screwplate. The advantage of this arrangement is obvious. Right or left thread dies may be used and the ratchet used in either instance.

What I claim as new is-= ratchet-ring journaled over the ratchet-surface back of the shoulder A and a ratchetpaWl in said ring operating on the ratchetteeth of the stock.

In testimony whereof I affix my signature in presence of two Witnesses.

CELESTIN POIROT.

lVitnesses:

H. O. LORD, J OHN S. BILLING. 

